Electric Mode
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The hybrid electric system operates in the electric mode when the vehicle is propelled by the electrical power stored in the high voltage traction battery. The torque is supplied to the output shafts by the traction motor, the generator motor, or a combination of both. This is a preferred mode whenever the desired torque is low and the electrical system rather than the engine can produce it more efficiently. The electric mode is also used in reverse because the engine can only deliver torque in a forward direction.